Pressure boosting pump and hydrogen supply system

Abstract

In a pressure boosting pump and a hydrogen supply system, included are a cylinder having a compression chamber, a suction valve configured to cause a low-temperature fluid to be sucked into the compression chamber, a piston movably supported on the cylinder and configured to compress the low-temperature fluid in the compression chamber, a discharge valve configured to cause the low-temperature fluid in the compression chamber to be discharged, and a piston ring provided on an outer periphery of the piston. The piston ring has a piston ring main body positioned closer to an inner peripheral face of the cylinder and an inner ring positioned closer to the center of the piston than the piston ring main body is. The inner ring has a hardness lower than a hardness of the piston ring main body.

1 . A pressure boosting pump comprising:
 a cylinder having a compression chamber;   a suction valve configured to cause a low-temperature fluid to be sucked into the compression chamber;   a piston movably supported on the cylinder and configured to compress the low-temperature fluid in the compression chamber;   a discharge valve configured to cause the low-temperature fluid in the compression chamber to be discharged; and   a piston ring provided on an outer periphery of the piston, wherein   the piston ring has
 a piston ring main body positioned closer to an inner peripheral face of the cylinder, and 
 an inner ring positioned closer to a center of the piston than the piston ring main body is, and 
   the inner ring has a hardness lower than a hardness of the piston ring main body.   
     
     
         2 . The pressure boosting pump according to  claim 1 , wherein
 the piston ring main body is formed of a PEEK-based material having polyetheretherketone as a main component, and   the inner ring is formed of a PTFE material having polytetrafluoroethylene as a main component.   
     
     
         3 . The pressure boosting pump according to  claim 1 , wherein
 the piston ring main body has a high-pressure piston ring main body positioned closer to the compression chamber and a low-pressure piston ring main body positioned on an opposite side of the high-pressure piston ring main body from the compression chamber, and   the low-pressure piston ring main body has a hardness of lower than a hardness of the high-pressure piston ring main body.   
     
     
         4 . The pressure boosting pump according to  claim 3 , wherein the hardness of the inner ring is less than or equal to the hardness of the low-pressure piston ring main body. 
     
     
         5 . The pressure boosting pump according to  claim 3 , wherein
 the high-pressure piston ring main body is formed of a PEEK-based material having polyetheretherketone as a main component, and   the low-pressure piston ring main body is formed of a PTFE material having polytetrafluoroethylene as a main component.   
     
     
         6 . The pressure boosting pump according to  claim 1 , wherein
 the piston is formed with an annular groove on an outer periphery,   the piston ring main body is disposed at an outermost part of the annular ring in a radial direction,   the inner ring is disposed inside the piston ring main body in the radial direction in the annular groove,   a backup ring is disposed inside the inner ring in the radial direction in the annular groove, and   the backup ring is formed of stainless steel.   
     
     
         7 . The pressure boosting pump according to  claim 1 , wherein
 the piston ring includes a plurality of piston rings provided spaced apart from each other in a direction in which the piston moves,   the piston is provided with a wear ring each on one side and another side of the piston rings in an axial direction, and   the wear ring is formed of a PTFE material having polytetrafluoroethylene as a main component.   
     
     
         8 . A hydrogen supply system comprising:
 a compression device including the pressure boosting pump according to  claim 1  configured to compress liquid hydrogen as a low-temperature fluid;   an evaporation device configured to vaporize the liquid hydrogen compressed by the compression device; and   a dispenser configured to supply the hydrogen gas vaporized by the evaporation device.